Comparison of complete blood counts in samples obtained from healthy dogs and cats by use of standard and microsample blood collection tubes

Abstract

To compare results of a CBC performed on blood samples obtained from healthy dogs and cats by use of standard and microsample collection tubes. Evaluation study. 29 healthy client-owned animals (14 dogs and 15 cats). A blood sample (3 mL) was collected from each animal; 2.5 mL was transferred into a vacuum tube that contained sodium EDTA, and 0.5 mL was transferred into a microsample tube that contained sodium EDTA. Variables evaluated were total numbers of RBCs and WBCs, hemoglobin concentration, Hct, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration (MCHC), mean platelet volume, and plasma total protein concentration as well as neutrophil, lymphocyte, monocyte, eosinophil, basophil, and platelet counts. Results for the 2 types of tube in each species were compared by use of Pearson correlation coefficients, Passing-Bablok regression analysis, and Bland-Altman analysis. The Pearson correlation coefficient was low for basophil count in cats and moderate, high, or very high for all other variables. Constant and proportional biases were identified for MCHC in dogs by use of Passing-Bablok regression analysis, although the mean difference between types of blood collection tubes was small. No evidence of constant or proportional bias for any other variable was revealed by regression analysis or Bland-Altman analysis. Samples obtained from healthy dogs and cats by use of microsample blood collection tubes provided clinically equivalent CBC results, compared with results for samples obtained by use of standard blood collection tubes, and minimized the total sample volume collected for diagnostic testing.